Tính nhanh (145 x 99 + 145 ) - ( 143 x 102 – 143 × 2 ) + 54 x 47

* Hướng dẫn giải

(145 x 99 + 145 ) - ( 143 x 102 – 143 × 2 ) + 54 x 47 - 47 x 53 - 20 - 27

= 145 × (99 + 1) – 143 × (102 – 2) + 47 × (54 – 53) – (20 + 27)

= 145 × 100 – 143 × 100 + 47 × 1 – 47

= 100 × (145 – 143) + (47 – 47)

= 100 × 2 + 0

= 200